Mattress tufting machine



Dec. 14, 1943. E. n MCROSKEY 2,336,741

' MATTRESS HTUFTING MACHINE Filed April 19, 1938 4 Sheets-Sheet 1 INVENTOR. L G/Ward Z fifflosl eg ATTORNEYS.

Dec. 14, 1943.

nauunnu E. L McRosKEY MATTRESS 'IUFTING momma Filed April 19., 1958 4 Sheets-Sheet 2 INVENTOR.

Fowaro z. mew 6 ATTORNEYS.

Dec. 14, 1943. E. L. McRosKEY MATTRESS TUFTING MACHINE 4. Sheets-Sheet 3 Fil'ed Apt-i1 19; 1938 NW m l IE-.2

ATTORNEYS.

Dec. 14, 1943. E, 1. MOROSKEY 2,336,741

I MATTRESS TUFTING MACHINE 'Filed April 19, 1958 4 Sheets-Sheet 4 INVENTOR- Za/ward L. M Poske ATTORNEYS Patented Dec. 14, 1943 UNITED STATES PATENT OFFICE MATTRESS TUFTING MACHINE Edward L. McRoskey, San Francisco, Calif.

Application April 19-, 1938, Serial No. 202,852

8 Claims.

This invention relates to mattress tuftinglmachines and has for its objects improvements and refinements in machines generally .of the character disclosed in my United States Letters Patent No. 1,977,856, bearing date of October 23, 1934, several of said objects, specifically, being a "mattress tufting machine having mattress com- ,pressing'elements that are substantially balanced at all positions of the elements without the necessity of auxiliary counter weights, and also a machine in which the mattress compressing elements simultaneously move toward and away from each other with the mattress between aid elements instead of such movement being merely relative, :with one of the elements stationary. Other ob- ,jects are the provision of a more simple, compact and efiicient machine than heretofore with the operating parts either concealed or disposed so as to not interfere with the mattress tufting operation nor to accidentally injure the mattress. Other objects and advantages will appear in the drawings and specification annexed hereto.

In the drawings,

Fig. lis a side elevational view of the machine broken in length to accommodate the sheet, parts being in section and broken out for clarity.

Fig.2 is a plan view of one end of the machine on y.

Fig. 3 is an end elevational view of one end of the machine.

Fig. 4 is a sectional view of the machine taken along the line 44 of Fig. 1, certain elements being shown in elevation.

Fig. 5 is an enlarged sectional view of one of the parts of the machine, taken along the line -55 of Fig. 1 showing the means mounting the compressing elements in elevation and the construction of such means.

Fig. 6 is an enlarged elevational'view of one Of the'switch actuating devices.

Fig. 7 is a sectional view taken along the line 'I-l of Fig. 5, and

Fig. 8 is a fragmentary view of an optional con- ,struction of a portion of my device.

Briefly described, my present invention has a pair of opposed frames with mattress compressing elements on each frame projecting toward the other for compressing a mattress placed between the frames at spaced points where the tufting is to be performed. The frames are preferably positioned horizontallyand are mounted to revolve bodily with the mattress held there- 'between, about a horizontal axis so as to permit reversing the position of the frames .and sides of the mattress relatively and to also permit the frames and mattress to be disposed .in vertical planes so as to enable operators to work on opposite sides of the frameat the same time. Insofar as these points in general, are concerned, they are old. However, heretofore, it has been necessary to counterbalance the frames to facilitate revolving the frames, or to dispose the pivots on which the frames revolve so that the frames will be balanced for turning when the frames .are in mattress compressing relation, and when not in such relation, then the frames would be out of balance on said pivots. 7

Also, heretofore, one frame only was mounted for movement toward the other frame, which other frame was stationary, except when revolved, and consequently the movement effective for-compressing and releasing a mattress was accomplished by one frame only.

With my machine, herein described, the frames are balanced on their pivots at all times without the use of counter weights, and the frames move simultaneously toward and away from each other to compress and to release the mattress, hence the time for compressing and for releasing the mattress is reduced in half where the same rate of speed is employed as in the older machines.

Certain'safety and time saving features of my invention, as well as other advantages, due to the construction of my machine will be described more in detail in thefollowing description.

In detail (Fig. 1), my machine comprises a pair of upright standards I, 1', adapted to be supported on a floor, and a pair of spaced, opposed, main frames 2, 2' extend horizontally between said standards and are supported thereby. "Each of the main frame members carry on their adjacent sides, an auxiliary frame 3 that comprises cross bars 3' (Fig. 2), extending'transversely relativ to the plane in which the standards are disposed when the main frames are in horizontal planes, which is the normal-position of the main frames when in mattress compressing and releasing position. Carried by the cross bars of each auxiliary frame are the mattress compressing elements 4, which elements are in rows or staggered, but the elements on one auxiliary frame are always directly opposed to the elements of the auxiliary frame opposite thereto, and said elements project into the space between the frames so as to compress the mattress at the points of the elements. Said elements and their positions are conventional, the elements having tapered sides extending convergently from the frames and are hollow with apertures at their outer sides for passing the cords carrying the tufts.

The mounting of the auxiliary frames on the main frames is such as to permit the auxiliary frames to be slidable on the opposed side member 5 of the main frame in the planes of the auxiliary frames, with quickly releasable locking means for locking the auxiliary frames in position, which mounting comprises strips 6 secured to and extending across said side members of the main frames, which strips act as guides for the auxiliary frames. The end cross bars of the auxiliary frames and the strips are apertured at spaced points for registration of said apertures, and a removable pin I extends through each pair of registering apertures to lock the auxiliary frames on the main frames. Projections 8 on the auxiliary frame are adapted to engage one of the side members of the main frame to function as a stop for properly positioning the auxiliary frames on the main frames. Thus in removing or changing frames, the operator merely releases the pins I on the lowermost auxiliary frame, and said frame is slid horizontally off the lowermost main frame, and upon revolving the frames to place the other main and auxiliary frame lowermost, the operation for removing said auxiliary frame is repeated. The new frames may then be slid into place, and when stops or projections engage the main frames, the apertures for pins 1 will be in registration for locking the auxiliary frames in place.

Also, heretofore, one frame only was mounted for movement toward the other frame, which latter frame was stationary, and consequently time Was lost in moving the frame to and from mattress compressing relation.

With my machine, the frames are in balance at all times without the use of counterweights, and

the frames simultaneously move toward and away from each other, thus reducing the time of movement to and from mattress compressing relation in half.

The main frames are supported on brackets 9, 9 which project into the space between the frames, and which terminate at their outer ends at opposite ends of the main frames, between end members I of the main frames, as shown in Figs. 4, 5. The end members ID connect between ends of side frame members of each of the main frames, and are preferably channel shape with their open side's facing each other. Also, in the direction of their length, said end members respectively extend slantingly from their ends toward a point centrally of said ends in a direction divergently outwardly of the end member opposed thereto. The pairs of opposed end members at opposit ends of the main frame are formed with aligned threaded openings II centrally of their ends, and are also formed with aligned bearings I2 at opposite sides of said central openings. Bearings I2 slidably receive rods I3, which rods are secured centrally of their ends to the outer ends of brackets 9, said outer ends being bored for passing the rods therethrough.

Threadedly extending through the threaded openings in end members ID are threaded posts I4, I4, the post I4 being adjacent standard I, and post I4 being adjacent standard I. The threads at the opposite ends of said posts I4, I4 are right and left respectively, so that upon simultaneously rotating posts I4, I4 on their axes, said .end members, and the main and auxiliary frames connected thereto will be moved toward or away from each other according to the direction in which posts I4, I4 are turned. The outer ends of brackets 9 rotatably support said posts I4, I4, at points intermediate the threaded ends thereof as best seen in Fig. 4.

The brackets 9, 9 are secured at their ends opposite their outer ends, to vertically disposed plates I5, I5, the plate I5 being adjacent standard I and plate I5 being adjacent standard I (Figs. 4, 5). Short horizontally extending, horizontally aligned, hollow shafts IE, IS rotatably extend through bearings in the upper ends of standards I, I respectively, to which shafts the plates I5, I5 are secured, thus the frames between said standards may be revolved about the axis of said shafts, which axis is centrally positioned between the opposed frames as best shown in Figs. 5, 7.

The threaded posts I4, I4 are rotated by means of bevel gears l1, l1 secured on the ends of short shafts I8, I8 that rotatably extend through hollow shafts I6, I 6, which bevel gears mesh with bevel gears, I9, I9 secured respectively to posts I4, I4. The end of shaft I8 opposite bevel gear II projects outwardly of standard I on said end and adjacent said standard I, is secured a sprocket 20 connected by chain 2| with a sprocket 22 that is secured on the outer end of a shaft 23 at the lower end of the standard. A sprocket 24 secured on shaft 23 adjacent sprocket 22 is driven by chain 25 which connects with a sprocket 26 on the driv shaft of motor 21.

Shaft 23 extends across between standards I, I through bearings thereon and on the end of shaft 23 outwardly of standard I, is secured a sprocket 28 connected by a chain 29 with a sprocket 30 that is secured on the outer end of shaft I8 which shaft I8 carries the bevel gear II that meshes with bevel gear I9.

The motor 21 is reversible, and from the foregoing, it will be seen that when the motor is energized to run in one direction, the posts I4, I4 will simultaneously be actuated to bring the mattress frames toward each other, and when run in the opposite direction, the frames will be moved apart, and at all times said frames will be equally spaced at opposite sides of the aligned axis common to shafts I4, I4, IE, IS. The frames also, may be revolved about said axis, since shafts I6, I6 carry said frames by the connections between said shafts and brackets 9, 9'.

The main frames 2, 2' including the various elements carried thereby, are releasably secured in a plurality of planes, as desired, by means of a horizontal sliding rod 3I (Figs. 1, 5), extending slidably through the upper end of standard I. One end of said rod is adapted to engage in any one of the annular row of holes 32 formed in plate I5, which holes are equal distances from the axis of shaft I8. Said holes are four or more in number, four being shown in the drawings as being equally spaced from each other and arranged so that the rod 3| will lock the plate I5, and consequently the frames 2, 2 in horizontal planes, with either frame 2, or 2' uppermost, as the case may be, or said rod will positively lock said frames in position in vertical planes with frame 2, or 2 positioned in one side or the other of the axis of revolution thereof, as desired. The rod 3| is provided with a handle 33 that extends outwardly through a horizontally extending slot 34 (Fig. 2), in the standard for manipulation of rod 33. Said slot 34 is notched out along a side at two spaced points for receiving the handle upon revolving the same on the shaft axis,

one notch holding the pin in locked engagement with an opening in plate l and upon moving the handle laterally out. of said 'notch and then longitudinally of the rod 3! a direction away from plate l5, the rod 3| will be disengaged from the plate and the handle may then be moved laterally into the second notch to hold the rod out of looking position whereby the frames may be revolved about the axis of shafts I8, [8.

Between holes 32 are relatively shallow recesses 32 (Fig. 5), that function to receive the end of locking rod 3! to hold the frames 2, 2 inclined slightly relative to horizontal, to facilitate sliding a mattress between said frames, but upon the weight of the mattress on the lowermost frame, the rod will automatically slip out of the recesses, due to the tapered end of the rod and to the shallowness of the recesses, and said frames will swing to horizontal where the rod 35 will automatically slip into the hole 32 coming in registration therewith, by reason of coil spring 35 (Fig. 1), connecting between'the standard and a member, later described, which member is drawn by the spring against the outer end of said rod (il at all times.

Means is provided for limiting the movement of the frames 2, 2 toward and away from each other which means comprises a conventional toggle switch 36 (Fig. 6), staticnarily supported on standard I. Said toggle switch, has the usual actuating lever 36', and which lever is actuated in opposite directions to break the circuit to motor 21, which circuit is established by a conventional switch 31 having a stop button, a forward and a reverse button, the stop button when actuate-d, stopping the motor and preventing any further actuation thereof by the forward or reverse buttons, until released. A post 38 (Figs. 3, 6), threaded at one end is rotatably supported on standard I by a bracket 39, the threaded end of said post projecting below the bracket and the opposite end being unthreaded and extending above the bracket. Said opposite end of post 33 carries a bevel gear 40 adjacent and below end of shaft 18 that projects, outwardly of standard I, which gear 46 meshes with a bevel gear ll. Bevel gear 4! is splined on shaft 58 to permit sliding thereof on said shaft, and said gear M also carries a peripherally grooved hub 42 for receiving in the groove of said hub at opposite sides of said hub, a pair of pins The pins &3 received in the annular groove in hub 42 project toward each other from a pair of generally vertical bars 44, which bars are rigidly connected at their upper ends by a cross bar 5 which cross bar is positioned to yieldably engage the outer end of rod 31 at all times by the action of coil spring 35 (Fig. l). The lower ends of bars 44 are connected together at a point spaced below hub 32, which lower ends are supported by horizontal pivots to a bracket 45, the bracket 46 being mounted on standard l.

The threaded lower end of post 3.3 carries a travelling switch actuating member ll (Figs. 1, 3, 6), adapted to move along the threads of the post upon rotation of said post. Said member includes an elongated plate 4'5 (Fig. 6), with lateral projections 48 extending at right angles to one side thereof, which projections extend across opposite sides of the switch lever 36. Adjacent each of the projections 48, and between said projections, are plates 59, adapted to engage the switch lever 35' at one side or the other thereof to actuate said switch 36 upon movement of said member 4'! upwardly or downwardly. Said plates 49 are preferably yieldably mounted on plate 4'! to slightly yield upon engaging the switch lever should the pressure between the plates 49 and the switch lever be excessive, which mounting includes a leg 49 on each plate 49 positioned against the plate 41', said leg being slotted to receive a pair of bolts 50 that are secured at one end to plate 4'! and headed at their outer ends for retaining the legs 49' against the plate 41'. The projections i8 are apertured to slidably pass rods 5| respectively secured to each of plates t? and a coil compression spring 52 is carried on each of said rods reacting between the plates 4? and projections 48 all as seen in Fig. 6'.

Member 41 also carries a lateral projection that is bored out to slidably pass a guide rod 53 disposed alongside post 38, one end of said rod being secured to bracket 39. Thus member 41 is slidable on rod 53 but cannot rotate on post 38.

The switch 3'! carrying buttons for causing actuation of the motor 2'! oppositely and which switch also carries the stop button for electrically disconnecting the motor from being actuated, is supported on a bracket 54 (Fig. 2), which bracket is secured to standard and connected to bar rod 3! (Figs. 1, 2), is a plate 55 that is adapted to slide over the stop button 56 of switch 31 to automatically depress the same upon moving the rod 3| for releasing the frames 2, 2' for revolving thereof and thus to prevent the motor 21 from being actuated when said rod 3| is in unlocked position. The stop button projects outwardly of the switch box (Fig. 2), while the other two buttons 51, 58 for causing actuation of the motor oppositely, are depressed in recesses in said box, hence the buttons 51, 58 are not actuated by plate 55. Also when rod 3| is moved to unlocked position, whereby the frames 2, 2' may be revolved, it is seen that bevel gear 4| is disengaged from meshing with spar gear 4%, consequently the switch actuating member 4! y is out of driving connection with the motor 21 when the frames 2, 2 are unlocked for revolving thereof on the axis of shafts l8, l8.

This latter feature of disconnecting gears 4.0, i! is a safety feature to prevent upsetting the timing of switch'member 41, since when this member is disposed on the post 38 for actuating switch lever 36 at a fixed point of compression of the mattress between the mattress compressing elements on frames 2, 2', such point should not vary except when a readjustment is made. to accommodate various sized mattresses. If by any chance the motor 2'! were actuated'when the frames were unlocked, the switch actuating member 41 would remain idle until the frames were in locked position.

I also preferably provide a conventional overload switch 59 (Figs. 1, 3), in the electrical circuit to automatically break the circuit to the motor 21 in case of overload so as to preven injury to the machine.

On at least one of the posts it ateach end of frames 2, 2, and between the frames, I find it desirable to secure .to a relatively soft and relatively thick washer 5t against a flange ti on such post, which flange may be adjustably secured on said post and adjacent one of the outer ends of at least. one of said posts H at opposite ends of the frames I provide a similar flange and washer 6-0. The washers 60 are adapted to be engaged by the bearings of the end members of the frame when the frames are moved toward each other to the limit of their movement, and the washers 60' are adapted to engage the bearings of frames I!) at their outer sides when the frames are moved apart to their limit of such movement. Thus, should the motor 21 tend to coast after the frames are together or apart and after switch lever 36 is actuated the frames will be cushioned against too abrupt checking of their movement, and also, should the motor circuit not be properly broken by switch 36, the overload switch will be broken during compression of the rubber washers, or bumpers 60, 60'.

The electrical circuit is conventional, and in the illustration, I show a conduit 62 (Fig. 1), for wires from the main power line leading to over.- load safety switch 59, and from said overload switch conduit 63 carrying wires to motor 21, and also a conduit 64 carries wires leading to switch 36 and conduit 65 extending from switch 38 to the switch 31. The circuit used, being conventional, is not shown in detail, since such details are conventional and readily understandable to anyone skilled in the art.

In operation, with the frames locked in horizontal planes as shown in Fig. 1, the operator presses lower switch button 58, and the motor 21 is actuated to turn posts l4 for simultaneously moving the frames 2, 2' apart to mattress receiving position. When switch actuating member 41 will simultaneously move upward on post 38 until lower plate 49 engages toggle switch lever 36' to throw the latter to one side and to stop the motor. The operator then slides an untufted mattress to between frames 2, 2' and onto the mattress compressing elements 4 of the lower auxiliary frame 3. When the mattress is so positioned, the switch button 51 is pressed, and the frames 2, 2' with the mattress therebetween, simultaneously move toward each other, with said frames always substantially equal distances from the axis of shafts l8, I8, about which the frames may be revolved. As soon as the upper plate 49 on switch actuating member 41 reaches toggle switch lever 36' and throws the same, the motor 21 again stops and the mattress compressing elements 4 are pressed into opposite sides of the mattress to the desired degree for tufting. The rod 3| is then slid outwardly by manipulation of handle 33 to lock the handle and rod in position with the rod disengaged from plate I5 that carries the holes 32 and the operator can then revolve the frames about the axis of shafts l8, l8 unti1 the frames are in vertical planes, when handle 33 is released from its notch in slot 34 and spring 35 will func tion to force the end of the rod in one of the holes 32 in plate Hi to again lock the frames against turning, and with the mattress in a vertical plane, an operator may stand on each side of the mattress to tuft the same. As already explained, when rod 3| is moved to unlocked position for turning the frames, the stop button 56 is automatically actuated by such movement to electrically disconnect the motor, and also the switch actuating member 41 is mechanically disconnected from actuation by the motor at the same time, which connections are restored, however, as soon as the frames are locked against turning.

If desired, the frames may, of course, be completely reversed and locked in reversed position, with frame 2 uppermost. It is immaterial, however, which frame is uppermost when the frames are in horizontal planes.

After tufting, the frames are again unlocked so as to be turned to horizontal position, and switch button 58 is again actuated to separate the frames preparatory to inserting another mattress.

The recesses 32 in plate l5 are generally used where the mattress to be inserted between the frames is taken from a height that would make it awkward to lower the same to slide between horizontally disposed frames. The operation involving the employment of recesses 32 has already been fully explained.

In Fig. 8 is shown an optional construction of the mechanism for disconnecting the driving connection between gear 40 and shaft [8 of Fig. 1. In this form of the invention the parts similar to those in Fig. 1 are numbered the same, but are primed. A clutch member 10 is secured on the outer end of shaft l8" having recess H formed therein for receiving dogs 12 on the adjacent end of a shaft 13 in alignment with shaft 18'. Bevel gear M is splined on shaft 13 and is held in engagement with gear 40 at all times by bearing I4 mounting shaft 13. The shaft 13 is movable axially with movement of bars 44 by pins 15 slidable in groove l6 on a sleeve secured to shaft 13. The bearing I4 is formed on bracket 46 which carries the bearing 39' for shaft 38. Thus the dogs 12 will always directly enter recess II when the mattress frames are in horizontal position, and there is no chance of improper meshing of gears 40', 41 since these are always in mesh, and the switch device 41 cannot be accidentally thrown out of proper relation for throwing the switch at the correct points as might occur where the gears themselves are physically connected and disconnected.

It is thought apparent that the balancing of the frames 2, 2 for revolving is a substantial improvement in the art, and also the simultaneous movement of said frames toward and away from each other affects an appreciable saving in time. Furthermore, the use of a drive shaft 23 connecting between the frame actuating gears at opposite ends of the machine eliminates the use of sprocket chains extending between the frames, as has been done previously, since the use of such chains causes grease and dirt to fall on the mattresses, and they readily catch dirt and lint.

Having described my invention, I claim:

1. In a mattress tufting machine that includes a pair of spaced, opposed, parallelly disposed -mattress compressing frames, means supporting said frames in spaced paralle1 relation for simultaneous movement of the frames toward and away from each other, means for causing said movement of the frames including an electric driving motor in an electrical circuit and an operating connection between the said first mentioned means and said motor, control means connected with and. actuated by the motor for stopping movement of the frames toward and away from each other at predetermined points, means mounting said frames for revolving in a path of travel about an axis, means releasably locking said frames in a plurality of positions in said path of travel against revolving in said path, means for releasing said locking means to permit the frames to revolve, and means actuated by release of said locking means disconnecting said control means from actuation by said motor upon actuating said locking means to release said frames for revolving thereof.

2. In a construction as defined in claim 1, the

means for disconnecting said motor from said control means including a rotatably mounted threaded post and a member carried by the threads of said post for movement of said member along said threads longitudinally of the post upon rotating said post, separable driving connection between said post and motor, and a switch in said circuit positioned to be engaged by said member for actuation thereby.

3. A mattress tufting machine comprising a pair of spaced, opposed, horizontally extending, parallel, mattress compressing frames, a reversi ble motor in an electrical circuit operably connected with said frames for moving the frames toward and away from each other and means supporting said frames for such movement, means for actuating said motor to cause said movement; means for stopping said motor at predetermined points of movement of said frame comprising a threaded rod, means mounting said rod for rotation thereof, a switch actuating member by the threads on said rod for movement therealong longitudinally of the rod upon rotation of said rod, a mechanical driving connection between said motor and rod for rotating the latter upon actuation of the motor, said member being positioned to engage and to actuate said switch at spaced points along said rod; and means for mechanically disconnecting the driving connection carried between said rod and motor at any point of movement of the member along said rod, means mounting said frames for revolving in a single path of travel about an horizontal axis, releasable lookin means for locking said frame against revolving, said means for mechanically disconnecting the driving connection between said rod and motor being connected and adapted to simultaneously release the locking means for turning said frame and to mechanically disconnect the driving connection between said rod and motor.

4. A mattress tufting machine comprising: a pair of mattress compressing frames in spaced, parallel, opposed relation; a pair of screws respectively positioned at opposite ends of said frames centrally of the widths of said frames provided with oppositely threaded end portions threadedly supporting said frames at equal distances from points centrally between the ends of said screws for simultaneous movement of said frames toward and away from said points when said screws are simultaneously rotated; standards outwardly of opposite ends of said frames supporting said frames for revolving in a common path about a central axis extending between said frames and through said points; plate elements carried by said standards for revolution about said axis and supporting said screws for rotation of the latter on their aXes a shaft parallel with said axis rotatably supported at its ends on said standards in a position wholly outside said path; drive means adjacent each of said standards connecting the ends of said shaft and the screws for simultaneously revolving said screws upon rotation of said shaft; and means for so revolving said shaft.

5. In a construction as defined in claim 4, said standards being adapted to support said frames on a floor for full revolution thereof about said axis; and the said opposite ends of said shaft being carried by the lower ends of said standards thereby enabling operators at opposite sides of said frames, when the latter are vertical, to tuft a vertically disposed mattress held between said frames without interference from said shaft.

6. A mattress tufting machine comprising; a pair of mattress compressing frames of similar weight and size in spaced, parallel, opposed relation; a pair of screws respectively positioned at opposite ends of said frames centrally of the widths thereof provided with oppositely threaded end portions threadedly supporting said frames at equal distances from points centrally between the ends of said screws for simultaneous movement of said frames toward and away from said points when said screws are simultaneously rotated; a pair of spaced, parallel guide bars respectively positioned at opposite sides of each of.

said screws equal distances from each screw and parallel with the latter; means rigid with said frames slidably engaging said guide bars for maintaining said frames parallel during movement of the latter toward and away from said points; means at opposite ends of said frames supporting said frames, screws and bars on the standards for revolving as a unit about a common central axis extending between said frames and through said points on said screws; means for rotating said screws including a driving connection between the screws at opposite ends of said frames disposed wholly outside the path followed by said frames during revolution of the latter so as not to interfere with the tufting operations of operators at either side of a mattress adapted to be supported between said frames.

7. In a mattress tufting machine having a pair of similar-sized mattress compressing frames respectively supporting mattress compressing members thereon and said frames having corresponding parallel side members, and end members respectively connecting between the corresponding ends of the side members of each frame; the said end members at each of the ends of said frame being generally of V-shape with their open sides in confronting relation; screws having opposite-- ly threaded ends at opposite ends of said frames having their opposite ends extending threadedly through the respective end members of said frames at opposite ends of the latter centrally of the ends of said end members; coaxial openings being formed in the opposite ends of the end members at each of the ends of said frames adapted to slidably pass therethrough parallel guide bars disposed at right angles to the planes of said frames; a pair of such parallel guide bars at each of the corresponding ends of said frames slidably extending through said openings; a pair of plate elements respectively positioned at opposite ends of said frames secured to guide bars and rotatably supporting said screws; a pair of coaxial hollow shafts carried by said plate elements mounted on the standards and adapted .to support said screws, bars and frames for revolution about the axis of said hollow shifts; a pair of coaxial inner shafts rotatably extending through said hollow shafts; intermeshing gears respectively carried by said screws and said inner shafts for rotating said screws upon rotation of said inner shafts; and means for simultaneously rotating said inner shafts.

8. In a construction as defined in claim I, the means for simultaneously rotating said inner shafts being disposed wholly outside the path of revolution of said frames when the latter are rotated about the axis of said hollow shafts.

EDWARD L. MCROSKEY. 

